The present invention relates to dry chemical formulations which undergo an exothermic, or heat-liberating action when contacted with water, ice or snow. Chemical deicing agents, also included in the formulations, are assisted in their normal functioning by the said liberted heat. One component of a formulation is always calcium oxide, or calcined limestone. The other component is a chemical deicer in its own right. Of special significance is the formulation in which the deicing agent is magnesium acetate. The novel formulations accelerate the normal deicing of roads, highways, walkways and parking lots.